It’s when three separate celestial events - a supermoon, a blue moon and a full lunar eclipse - occur simultaneously

Dave Reneke, a writer for major Australian publications including Australasian Science Magazine and who’s based on the Mid North Coast, says the eclipse starts at around 11.50pm with full eclipse occurring around 12.30am.

The last time such a triple treat took place was in 1866.

“No human alive has ever seen this before and it will not be seen again until 2028 – on December 31 to be exact,” Dave added.

It will be the third of summer's four supermoons, the phenomenon where the full moon appears bigger and brighter because it is "at perigee" - the point in its orbit when it is approaching Earth at its closest.